The present invention relates to a crash guard device for a rail vehicle.
FIG. 1 of German Patent Application No. 196 35 221.5 shows a conventional crash guard device for rail vehicles.
The device includes energy dissipating elements having a box-shaped structure and a rectangular cross-sectional shape arranged between the main frame of the rail vehicle and the buffer elements. These energy dissipating elements compensate for crash energy that exceeds the energy absorbing power of the buffer elements. German Patent Application No. 196 35 221.5 describes. The embodiment used is characterized in that the cross-sectional shape of the energy dissipating element arranged in each case between the buffer element and the main frame in the form of a closed box-shaped carrier becomes steadily wider in the direction from the buffer element to the main frame. The buffer element is a standard buffer known as a plunger buffer which is known. Such a plunger buffer is composed essentially of a buffer plate 10 mounted on an outside box 11 and inverted over an inside part 12, as shown in FIG. 1 of the patent application cited above. Outside part 11 and inside part 12 can be displaced into one another, and an energy dissipating element, e.g., in the form of a frictional spring, optionally with an additional hydraulic capsule, is arranged inside part 12.
A disadvantage of the conventional known crash guard device is that due to an tandem connection of the conventional energy dissipating element with a standard buffer, based on total length L of the crash guard device, comparatively little active length is available for absorbing energy. Of the total length of the standard buffer element, only a comparatively small distance is available for pushing outside part 11 over element 12 (distance of travel of the buffer element). In addition, it should be recalled that the full length is not available with the energy dissipating element, but instead a residual length always remains in the compressed state.
According to the present invention a significantly greater active length for absorbing energy is made available with the same total length L.
It should be pointed out here that according to the latest international guidelines for the safety of rail vehicles (ERRI B 205/RP1), a minimum uptake energy of 1 MJ is specified for deformation zones. In addition, according to these guidelines, a deformation path of 1 meter should not be exceeded. However, UIC 566 specifies a minimum strength of 2000 kN for the structure of the rail vehicle. To absorb the required minimum energy of 1 MJ with a force level below 2000 kN, a deformation length of more than 0.5 meter is necessary. Otherwise, the entire structure of the rail vehicle would have to be designed for a higher strength. There are no conventional crash guard devices at the present having a deformation greater than 0.5 meter.
Through an embodiment of a box-shaped energy dissipating element according to the present invention that has an insertion area and a buffer plunger that fits in it and is inserted into it, the energy dissipating element can be designed to be much longer in comparison with conventional devices so that on the whole, a much greater active length is available for dissipating energy. To be able to fully utilize this length, the insertion area must not abut against the main frame when the energy dissipating element crumples, so the main frame is provided with suitable recesses.
Advantageous embodiments of the energy dissipation element have a greater stability with respect to lateral forces and torques and eccentric longitudinal forces, torques which deform only through axial buckling in a crash. This makes use of the finding that when deformation is caused in the box by a crash, the deformation stops first in the area of the end of the box, where the box has a smaller cross section. Since the deformation resistance of the box increases progressively due to the increase in cross section in the direction of the main frame, buckling, which progresses axially from the end of the box to the main frame, stops so that uncontrolled collapse such as that which could occur with a box having a constant cross-sectional shape can be ruled out. In another advantageous embodiment, the box is in the shape of a rectangle, at least in the area of the main frame, with the longer sides being positioned horizontally. The lateral supporting forces of the energy dissipating element can be increased in this way. To further increase the lateral supporting forces, lateral reinforcements may be provided according to the present invention, also causing a progressive increase in resistance to axial collapse. Thus, this mostly prevents the deformation from extending to the following structure (main frame). To further ensure a progressively continuous deformation from the end of the box to the main frame through axial collapse, the structure of the box or the energy dissipating element may be provided with weak points in defined areas according to the present invention e.g., in the form of notches in the wall of the box. These weak points can predetermine where and in which order the walls of the box are deformed due to parallel successive folding. The defined weaknesses in the structure of the box are arranged for example, only in the front area of the box or they decrease toward the rear area in the direction of the main frame. The structural measures described here increase safety, so that the box is deformed only due to axial collapse (compression deformation), which is associated with a high energy dissipation, but uncontrolled buckling (bending deformation) of the box, which causes only a slight energy dissipation can be largely ruled out even with eccentric induction of the crash energy.
Yet another embodiment according to the present invention has the particular advantage that after deformation of the energy dissipating element, only the outer box need be replaced, while the insertion area and the buffer plunger can be reused, optionally as a separate buffer element.
The present invention will now be explained in greater detail below.